class ClassToStruct { int x; }; class ClassToUnion { int x; }; struct StructToClass { int x; }; struct StructToUnion { int x; }; union UnionToClass { int x; }; union UnionToStruct { int x; }; ClassToStruct class_to_struct; StructToClass struct_to_class; ClassToUnion class_to_union; UnionToClass union_to_class; StructToUnion struct_to_union; UnionToStruct union_to_struct;